/**
 * Boolean
 *  - true
 *  - false
 *  True和False是有效的标识符，并不是布尔值
 *  所有其他数据类型都有其相应的布尔值等价形式
 */

//1.String
console.log(Boolean('')) //false
console.log(Boolean('li')) //true
//2.Number
console.log(Boolean(0)) //false
console.log(Boolean(NaN)) //false
console.log(Boolean(1)) //true
console.log(Boolean(Infinity)) //true
console.log(Boolean(-Infinity)) //true
//3.Object
console.log(Boolean(null)) //false
console.log(Boolean({name: 'li'})) //true
//4.Undefined
console.log(Boolean(undefined)) //false


